The present application is an improvement of a valve actuating mechanism described and claimed in U.S. Pat. No. 3,508,446, assigned to the same assignee as the present application.
This invention relates to a safety valve apparatus, and more particularly, to an improved valve actuating mechanism for use in a safety valve apparatus.
Previously known valve actuating mechanisms for use in safety valve apparatus have provided means for closing safety valves under an emergency condition, thereby shutting off a flow of fluid. Such valve actuating mechanisms have been useful in fluid systems wherein the fluid is under high pressure as well as under low pressure. In a fluid system where the fluid flows under high pressure, emergency closure of the safety valves, thereby stopping the flow of fluid, often causes a pressure shock in the fluid system. The resultant effect from the pressure shock is damage to other equipment connected in the fluid system, such as gauges, pressure regulators, and control devices. Aversion of pressure shock in the fluid systems during periods of normal closure of the safety valves is a necessary requirement to enable fluid systems to function properly without constant repair.
It is therefore an object of the present invention to provide a valve actuating mechanism which opens and closes a safety valve under normal operating conditions for use in compressible and incompressible fluid systems.
It is another object of the present invention to provide a valve actuating mechanism which opens and closes a safety valve under normal operating conditions while maintaining the capability of a safety valve to move from an open position to a closed position in response to an emergency signal.
It is still another object of the present invention to provide a valve actuating mechanism which opens and closes a safety valve under normal operating conditions for use in compressible or incompressible fluid systems at high pressure with minimum fluid pressure shock, while maintaining the capability of a safety valve to move from an open position to a closed position in response to an emergency signal.
It is another object of the present invention to provide a valve actuating mechanism that is capable of use in compressible or incompressible fluid systems, including high pressure fluid systems, whereby the movement of the valve actuating mechanism which opens and closes a safety valve is controlled by a reversible motor means.